Solenoid structure and control



Feb. 2, 1960 J- T. BLAK T E 2,923,864

SOLENOID STRUCTURE AND CONTROL Filed Sept. 27, 1955 /5A L9 20 lo /5 & /4 2/ /8 /5A 60,

dame-s r 54 0/05 TONE I N V EN TOR.

United States Patent SOLENOID STRUCTURE AND CONTROL James T. Blakistone, Alhambra, Califi, assignor of thirty percent to Marvin Goodson and William E. Hannam, Los Angeles, Calif., jointly Application September 27, 1955, Serial No. 536,905 7 Claims. (Cl. 317-1555) The present invention relates to an improved solenoid structure and a new control circuit therefor.

An object of the present invention is to provide an improved solenoid structure of this type which requires no energizing current in one operating position of the same.

Another object of the present invention is to provide a solenoid structure of this type in which the control current is relatively small in comparison to the operating current.

Another object of the present invention is to provide an improved solenoid structure involving the used of two members movable with respect to the windings in which the leakage flux is relatively small.

Another object of the present invention is to provide a solenoid construction of this character which may be made inexpensively.

Another object of the present invention is to provide a novel control circuit for a solenoid operated device.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

The single figure is a transverse sectional view through a solenoid structure embodying features of the present invention, and also shows in schematic form the novel circuit, embodying features of the present invention, connected thereto.

The solenoid structure incorporates two coils or windings 10 and 11 coaxially disposed on a brass tube 12, but spaced by a steel magnetizable ring 14, the perimeter of which abuts the inner. wall ofthe outer steel casing 15, which contains such coils and which is closed at opposite ends by the rings 16 and 17. The ring 16 is of steel and, while the ring 17 may be of steel, it is preferably of a non-magnetizable material such as, for example, aluminum, for purposes of minimizing leakage flux, considering the fact that it is mounted adjacent a specially constructed movable core member 18 which, in its unmagnetized condition, is pressed against the stop 19 by circumferentially arranged coil compressed springs 20 recessed in an enlarged portion 15A of the casing 15.

The core member 18 is generally in the form of a steel disc having a centrally disposed and axially extending cylindrical portion 18A which is slidably mounted in tube 12 and which has a conical end portion 18B adapted to be snugly received in a cooperating conical recessed portion 21A of the cylindrical steel core member 21, also slidably mounted in the tube 12.

The core member or plunger 21 has a rod 22 coaxially extending therefrom for attachment to a device (not shown) that is to be operated thereby. The core member 21 is mechanically coupled to a pair of single pole, single throw switches 24, 25, and the mechanical coupling therefor is indicated by the dotted lines 26, 27 and 28.

connected to the ungrounded terminal of the source 331 which may be AC. or DC. The other terminal of winding 11 is returned to ground through the series connected switches 24 and 32, and the other terminal of winding 10 is returned to ground through the switch 25 and the On-Ofi control switch 35, such switch 25 being ar-f ranged to short circuit a current limiting resistance 36.-

It is understood that while the provision of such resistance 36 and its short circuiting switch 25 is preferred, the same may be omitted, in which case the switch 35 is connected directly to one terminal of winding 11.

With the switch 35 in its closed position, as shown, an energizing current for winding 10 flows from battery 33, through winding 11, resistance 36 and switch 35, the resistance 36 serving to limit the flow of current through coil 10 under the conditions shown. The field thus set up by the coil 10 maintains the two movable core members 18 and 21 in attracted and contacting position to thereby maintain switch 24 closed, switch 25 open, and

switch 32 open.

When the switch 35 is opened, the energizing current for coil 10 is interrupted and the core member 18 is thus allowed to move to the left against the stop 19, under the influence of the biasing springs 20, to thereby close switch 32. When switch 32 is closed, an energizing current flows through the other coil 11 through the following path: from the source 33, winding 11 and switches 24 and 32, and, as a result, the core 21 is moved to the right. Near the end of such travel of the core member 21, the switch 24 is opened and the switch 25 is closed. Opening of switch 24 interrupts the flow of energizing current to coil 11, while closure of switch 25 results in short circuiting of resistance 36 to thereby condition the energizing circuit for the other coil 10 so that maximum energizing current may initially flow through coil 10 when switch 35 is subsequently closed.

It is noted that because of the two-coil construction, it is possible to achieve higher realizable forces than in the case with a single coil construction using a spring return. This is so since in the latter case all of the work which the solenoid is to do is accomplished in one direction. 7

Using the instant construction, the magnetic structure performs a push and pull stroke, and .the amount of force developed in such push and pull strokes may be in different rations depending upon the purpose intended to be achieved, this being accomplished simply by proper design of coils 10 and 11.

It is understood that the broad idea of using a two-coil solenoid construction is not new, but the instant arrangement avoids one of the disadvantages of the prior art structures. This disadvantage is obviated by the spring biased core member 18 which with the coil 10 deenergized, an air gap is provided between the core members 18 and 21 so that flux produced as a result of current flow in coil 11 does not tend to keep the core member 21 in its sealed position (i.e. its mostleft position in the figure). In other words, the springs 20 in this case assure the development of an air gap between the core members 18 and 21 so that leakage flux from coil 11 is of insufficient intensity to prevent the core 21 from moving to the right as intended upon energization of coil 11.

It is realized, of course, that other modifications may be made within the sphere of the present invention. For example, the member22, instead of extending to the Patented Feb. 2, 1960 that upon power failure, i.e. upon disconnection of the 1 sou rcc 33, the core member 21 remains in its position shown.

While the particular embodiments of the present invention have been shown and described, it will be obvious n os skilled in th art th changes. n mo i ic ti ns. y he made it out d p i g from this inventi n in s b eede asp s nd, t er f e, th aim the app n d c aims to c er a l such. chan e an od fi a ions as. fal th n the true. sp r t and sc pe of h s in vention.

I claim;

1., A solenoid construction including two windings, a common core member influenced magnetically by each of said windings to move said core member in opposite di ion a epa co memb r magnetically influneedenly by on f sa d inding said common r m mber co prising an e cng ted. memb r di pos d within said two windings Whijchare coaxially arranged, and said separate core member being in the form of a disc having a portion thereof extending coaXially into only said one windin a magnetizable casing enclosing said ngs, and said disc e ng ttr te le by on y said o n ng o id casing- 2. An arrangement, as, Set forth in, claim 1 including pring, meensncrm y bias ng, said. disc aw y from s i casing and from said common core member,

3. A solenoid including two windings, a common core member influenced magnetically by each of. said winds ings to move said core, member in oppositedirections, a separate core member influencedonly by one of said windings, a first switch operated by said common core member, a second switch operated by said separate core member, an energizing circuit for the other one, of said windings compr sin s lly s id t er winding, and ai first and second switches,

A solen id. arran emen as s t; for h in c aim. 3

n uding a third. switch. perated. by; said. commoncure, membe a curr nt lim ing r sistance conn ctedn: sh nt- Wlth aid third switch. a centrol switch, and n. en-

rgizing ci cuit for id one win ing inc uding s rially said one wlndlng, said third switch and said control switch.

5. nerrangen n or the ch racter; d scnb d cemextend to the left,

prising, in combination, a ings, a magnetizable cylindrical casing encircling said windings, a magnetizable disc closing one end of said casing, a magnetizable disc movably mounted with respect to the other end of said casing, spring means normally maintaining said movable disc away from said casing, a third disc in said casing separating said pair of windings, a core member in said pair of windings, said core member having a length less than the combined lengths of said two windings so that said windings when energized successively move the core, inv opposite directions, said movable disc member being attracted to'said casing only upon energization of one, of the said pair of windings to close aflux path which extends through said casing, said movable disc, and said third disc, the first mentioned disc, casing and third disc providing a closed flux path for flux developed by the other one of said pair of windings, said spring means serving to disestablish a flux path for said one winding when said one winding is deenergized.

6. An arrangement as set forth in claim 5, including a switch operated by said movable disc, a second switch, an energizing circuit for said other winding, said energizing circuit including said other winding, said second switch and the first mentioned switch.

7. An arrangement of the character described conic prising, in combination, a pair of axially aligned coils, a core member in said coils having a length less than the combined lengths of said two coils so that energize.- tion of one of the windings moves the core in e direction and energization of the other coil moves. the

- References Cited in the file of this patent ITED STATE PATENTS 707,967 Griscom s r Aug. 26, 1902 900,658. Bristol Oct. 6,; 1908 965,877 Dennis Aug. 2, 1910 1,142,852 Simon Junev 15, 1915 1,978,737 Bower Oct. 30, 1934 1,980,796, Goff Nov. 13, 1934 2,794,157 Chisholm May 28', 1 95? pair of axially aligned wind- 

